Drive for sewing machine cloth feeders



July 26, 1955 I w, ENGEL 2,713,839

DRIVE FOR SEWING MACHINE CLOTH FEEDERS Filed April 23, 1952 I 2 Sheets-Sheet 1 Fig.1. g

IN VEN TOR.

BY W Enqe/ Juiy 26, 1955 w. ENGEL DRIVE FOR SEWING MACHINE CLOTH FEEDERS Filed April 23, 1952 2 Sheets-Sheet 2 Wei-f BY IN VEN TOR.

gang E n @bhul /fffb United States Patent DRIVE F012 SEWING MACHINE CLGTH FEEDERS Wolfgang Engel, Bielefeld, Germany, assignor tn Gritzner- Kayser Aktiengeseiischaft, Karlsruhe-Duriach, Germany Appiication April 23, 1952, Serial No. 233,803 Claims priority, application Germany April 27, 1951 8 Claims. ((11. 112215) This invention relates to a drive assembly and more particularly has reference to means for driving the cloth feeder mechanism of a sewing machine. The inventive concept is especially efficacious for use with a cloth feeder mechanism wherein the cloth feeder is carried by a substantially horizontally disposed arm which is reciprocated L Yet another object of the invention is to provide a cloth feeder drive arrangement for sewing machines wherein means is included to change the elevation or vertical position of the cloth feeder mechanism during the advancing movement to compensate for the different types of cloth to be sewn.

And still a further object of this invention is to provide a drive assembly for use with cloth feeders of the type set forth which is relatively simple in structural detail, positive and efiicient in operation and which may be readily and inexpensively manufactured.

Broadly, the assembly comprises a connection between the feeder arm and a crank element, a double link, one arm of which is associated with the feeder arm while the other arm is associated with an eccentric rotatable about a horizontal axis, a crank arm movable through an eccentric path is connected to the pivot between the two link arms so that during advancing movement, the link arms are substantially straight while during the return movernent, the link arms are bent relative to each other and means is operatively connected with the eccentric to change the position thereof whereby the point of pivot between the eccentric and the arm of the double link may be changed to alter the elevation of the cloth feeder during the advancing movement.

With the foregoing and other objects in view, the invention consists in the details of construction, and in the arrangement and combination of parts to be hereinafter more fully set forth and claimed.

In describing the invention in detail, reference will be had to the accompanying drawings forming part of this application, wherein like characters indicate corresponding parts in the several views, and in which:

Fig. 1 is a view in side elevation, partly in cross section of the cloth feeder drive, the view looking from the looper side of the sewing machine.

Fig. 2 is a vertical sectional view taken along the line II-II of Fig. 1, the view looking in the direction of the arrows.

Fig. 3 and Fig. 4 are side elevational views respectively showing other positions of movement of the cloth feeder.

Figs. 5 to 8 inclusive represent diagrammatically the known ratios, and

Patented July 26, 1955 Fig. 9 depicts diagrammatically the path of the cloth feeder.

Referring to the drawings, it will be seen that the sowing machine is provided with a cloth carrier plate 1 and a stitching plate 2 is suitably fastened thereon. The plate 2 is formed with conventional openings 3 for receiving the teeth of a cloth feeder assembly 4. Studs 5 are supported beneath the carrier plate 1 and a drive shaft 6 for a looper unit 7 is journalled in the studs.

The cloth feeder is carried by an arm 8 located below the plate 1 and disposed in a substantially horizontal plane. The free end of the arm 8 is attached to a crank 9 which oscillates about a shaft 10, the means for turning the shaft not being shown. Hence, it will be appreciated that rotation of the shaft 10 will reciprocate the cloth feeder 4.

A bolt 11 is secured to the arm intermediate the ends thereof, and as illustrated in Fig. 2, arm 13 of a double link A or rocker is carried by the bolt by means of a split clamp 12. The arm 13 is connected to arm 14 of the double link by a pivot pin 15, the arm 14 being swivelled at its opposite end to a stud 16 mounted eccentrically on a plate 17 secured to one end of a shaft 18. An arm 18a is clamped to the shaft 18 and one end of an operating rod 19 is anchored to the arm 18a while the free end of the rod is connected to a hand lever 20 pivoted to a post 21 carried by the frame of the sewing machine. Manifestly, by manipulating the hand lever 20, the shaft 18 can be turned and thereby change the vertical position of the stud 16.

One end of a crank 22 is secured to the pivot pin 15 as denoted at 23 and the opposite end of the crank is attached to an eccentric 24 provided on the shaft 6.

From the foregoing description, it can be seen that the assembly includes but few cardinal working parts and briefly the operation of the assembly is as follows:

Rotation of the shaft 10 will oscillate the crank 9 and by reason of the arm 8 which connects the feeder with the crank, the feeder 4 will reciprocate and Fig. 5 shows the various parts when the crank 9 has moved to the limit of its movement toward the left. In this position, the arms 13 and 14 of the double link A are about straight or in the same plane. While the crank 9 moves in the opposite direction, the eccentric 24 turns from the location of Fig. 5, namely 25 to the position 26 illustrated in Fig. 6. Hence, the relationship of the arms 13 and 14, that is to say, the straight position of these arms, changes but little, so that during this full cycle or advancing movement, the cloth feeder 4 follows a substantial horizontal path which is denoted by the line connecting the positions 25 and 26 in Fig. 9.

During the oscillation of the crank 9 depicted in Fig. 4 toward its right end location, the eccentric 24 rotates from the position 26 in Fig. 6 to the position 27 in Fig. 7 and it will be seen that the arms 13 and 14 are bent with respect to each other and thus the cloth feeder 4 is moved downwardly with respect to the stitching plate 2 and the path corresponding to this movement is shown between the positions 26 and 27 in Fig. 9. Upon movement of the crank 9 in the other direction, the eccentric 24 will assume the position shown at 28 in Fig. 8 and this corresponds to the position 28 in Fig. 9. Since during this movement, the double link A is in the position with the arms 13 and 14 bent respecting each other, the position 28 will lie even lower and upon further oscillation of the crank, the cloth feeder 4 will move to the position 29 in Fig. 9 and into the location 25 shown in Fig. 5 with which its course is closed and the even advancing movement again started.

With regard to Fig. 1, the position of the stud 16 is such that feeder teeth project their greatest limit beyond the stitching plate 2 which is desired when thick cloth or material is being sewn and the hand lever 20 is in its central position. By moving the lever upwardly to the location denoted 210, the stud 16 can be lowered a short distance in the direction of the arrow 20% and thus the position of the cloth feeder relative to the cloth can be readily adapted to the thickness of the cloth. If, however, the lever 20 is swung downwardly to the position shown at 211, the stud 16 will be displaced to the position illustrated in Fig. 4 and consequently, the feeder teeth do not project above the stitching plate during the advancing movement of the feeder 4. This lowest location of the stud 16 is so selected that the arms 13 and 14 will bend an equal distance on both sides of their straight relationship during a complete movement of the feeder 4. Consequently, the path of the feeder is substantially horizontal, there being little displacement vertically so that the feeder will remain below the stitching plate 2 during its full movement.

The means for moving the cloth feeder in a reciprocatory manner with respect to the stitching plate may be termed a swinging-block linkage.

From the above description of the invention, it Will be apparent that many modifications of the same may be devised within the scope thereof and all such modifications are contemplated as may fall within the scope of the appended claims.

I claim:

1. In a sewing machine of the type having a stitching plate, a cloth feeder movable in a reciprocatory manner with respect to said plate by a swinging-block linkage comprising in combination, a rotatable shaft, a crank connected to the shaft, the movement of the crank oscillating the said swinging-block linkage, an arm carrying the cloth feeder, a pivot connection between one end of the arm and the crank whereby the arm is substantially perpendicular thereto, a rocker, a pivot connection between the rocker and the other end of the arm with the rocker substantially parallel with the crank, an adjustably mounted stud, a swivel connection between the other end of the rocker and the stud so that when the crank is rocked by the rotation of the shaft, the cloth feeder will be moved in a reciprocatory manner respecting the stitching plate and in parallelism thereto, and means associated with the said rocker for periodically changing the length of the rocker between the pivot connection of the rocker to the arm and the swivel connection to the stud so as to produce a periodic movement in a reciprocatory manner of the feeder in a transverse direction with respect and in addition to the movement of the feeder in parallelism to the stitching plate.

2. A sewing machine according to claim 1 wherein the means for periodically changing the length of the rocker comprises a first arm pivoted to the arm carrying the feeder, a second arm swivelled on the stud, a pivot pin connecting the first and second arms together and with the pivot pin being periodically actuated in a reciprocatory manner in a substantially transverse direction with respect to the direction in which the rocker extends so that when the pivot pin is reciprocated, the first and second levers are bent with respect to each other and are then brought into a straight position respectively thereby changing the length of the rocker periodically.

3. A sewing machine according to claim 2 wherein said pivot pin is actuated by a crank connected at one end to the pivot pin and eccentrically mounted at the other end to a rotatable shaft so that one complete rotation of such shaft is effected during one complete reciprocatory movement of the swinging-block linkage.

4. A sewing machine according to claim 3 wherein the first and second arms are in a straight position during one half of the reciprocatory movement of the swinging-block linkage and are in a bent position with regard to each other during the other half of the oscillating movement of the said linkage.

5. A sewing machine according to claim 4 wherein the said stud is eccentrically mounted on a shaft disposed horizontally respecting the stitching plate whereby rotation of the horizontal shaft adjusts the position of the stud.

6. A sewing machine according to claim 5 wherein the position of the stud closest to the stitching plate coincides approximately with the highest position of the eccentric so rotation of the eccentric in either direction from its highest position will lower the stud.

7. A sewing machine according to claim 6 wherein an arm is on said horizontal shaft, a lever connected to the arm effects turning of the shaft and the connection between the arm and lever is such that the mid location of the arm determines the position of the eccentric closest to the stitching plate.

8. A sewing machine according to claim 7 wherein when the stud is in its lowest position with respect to the stitching plate, the first and second arms will be displaced uniformly at both sides of a plane traversing the axis of the stud.

References Cited in the file of this patent UNITED STATES PATENTS 882,266 Noble et al Mar. 17, 1909 1,176,444 Hagelstein Mar. 21, 1916 1,817,727 Wohlpart Aug. 4, 1931 2,228,718 Best Jan. 14, 1941 FOREIGN PATENTS 807,164 Germany June 25, 1951 

